【单选题】138 Sound, prudent, but often unsophisticated judgement is called:
【单选题】下列关于苯的说法正确的是 ( )
A.
苯的分子式为 , 它不能使酸性 溶液退色 , 属于饱和烃
B.
从苯的凯库勒式 ( ) 看 ,78g 苯中含有碳碳双键数为
C.
在催化剂作用下 , 苯与液溴反应生成溴苯 , 发生了加成反应
D.
苯分子为平面正六边形结构 ,6 个碳原子之间的化学键完全相同
【简答题】[WJ-400-600]为了解决传输过程中的“走反路”问题,路由器使用(__)报文来解决。
【单选题】The sense of sound is one of our most important means of knowing what is going on around us. Sound has a waster product, too, in the form. of noise. Noise has been called unwanted sound. Noise is grow...
A.
Because the world is becoming more and more noisy.
B.
Because they have learned that noise is also a kind of pollution.
C.
Because noise is an unwanted waste for human beings.
D.
Because people knew little about noise before.
【单选题】56 Sound, prudent, but often unsophisticated judgement is called:
【单选题】下列有关苯的说法正确的是
B.
苯是重要的化工原料,主要是通过石油分馏得到的